Thursday, May 31, 2012

Global Warming Isn't Global

When thinking about something like 3°C warming by 2050, one thing to keep in mind (as I reminded myself today) is that that's the global average. But most people live on land, and average warming there will greater than warming over the oceans. And most people (90%) live in the northern hemisphere, where the trend is warmer still.

Here are the lower troposphere trends of different regions* as measured by UAH. (Uncertainties are statistical uncertainties, at the 95% confidence level; NH = Northern Hemisphere)

region

UAH LT trend
(°C/decade)

ratio to
Global trend

Globe

0.13 ± 0.02

1

Land

0.17 ± 0.02

1.3 ± 0.2

Ocean

0.11 ± 0.02

0.8 ± 0.1

NH Land

0.19 ± 0.02

1.4 ± 0.1

So perhaps as warming increases people will tend to move not just away from the equator, but to to small isolated islands, where (I suspect) the warming trend is more like that of their surrounding ocean than of land. Unfortunately, some of those islands will be underwater.

Perhaps really rich people will live on ships, and invite others in order to set them up as small independent countries of their own, a la Blueseed.

(*Of course, there will still be significant regional differences on smaller scales, too.)

6 comments:

While analyzing the Argo data, Willis discovered a sort of "cap" on the temperature in the tropics, a region where water vapor cycles act as the regulator, swamping all other variables naturally.Eschenbach and Argo on warmest ocean temps.

The equatorial region has already reached it's maximum temp, long before anybody moved there, and that's not bound to change any time soon.